TECHNICAL MANUAL
OPERATOR S MANUAL FOR
ADVANCED COMBAT HELMET (ACH)
2007 Gentex Corporation
TP0271 REV. 2 FEBRUARY 2007
WARNING SUMMARY
This warning summary contains general safety warnings and
hazardous materials warnings that must be understood and
applied during operation and maintenance of this equipment.
Failure to observe these precautions could result in serious
injury or death to personnel.
WARNING
For first aid treatments, refer to FM 4-25.11.
WARNING
For airborne and other high risk operations such as air
assault and rappelling/mountaineering, all seven ACH pads
must be worn at all times. Failure to observe this precaution
could result in serious injury or death.
WARNING
The hardware (nut) inside the ACH where the chinstrap
retention system webbing attaches to the ACH shell in four
places must be covered by padding during airborne and
other high risk operations such as air assault and
rappelling/mountaineering. The pads must be placed flush
with the rim (edge) of the ACH and completely cover the
hardware. Failure to observe this precaution could result in
serious injury or death.
a
WARNING
If you experience fit problems, tightness/looseness, or ACH
profile is too high or too low, refer to Sizing and Fitting
Troubleshooting guidelines. Failure to observe this
precaution could result in serious injury or death.
WARNING
If no NVG Front Bracket is used and the ACH has a hole
for the front bracket plug the hole with the 8-32 x 3/8 long
screw and post. See Chapter 4, Associated and Repair
Items List, for the appropriate part number.
WARNING
The rear pads must be placed flush with the rim (edge) of the
ACH for airborne operations. If you experience ACH rotation
during airborne operations, the rear pads can be placed so
that they extend ½ beyond the rim of the ACH. Placement
of the rear pads flush or beyond the rim (edge) of the ACH
prevents the hard shell from hitting your neck. (See Pad
Placement over Hardware (Front) and Pad Placement over
Hardware (Rear) illustrations.)
b
TABLE OF CONTENTS
Page
WARNING SUMMARY . . . . . . . . . . . . . . . . . . . . . . a
HOW TO USE THIS MANUAL . . . . . . . . . . . . . . . . . . iii
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . iv
CHAPTER 1 - DESCRIPTION AND THEORY OF
OPERATION
Equipment Description and Data . . . . . . . . . . . . . . . . . 1
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . 9
CHAPTER 2 - OPERATOR INSTRUCTIONS
Sizing and Fitting Instructions . . . . . . . . . . . . . . . . . . 11
Pad Configurations . . . . . . . . . . . . . . . . . . . . . . . 15
Pad Suspension Adjustment . . . . . . . . . . . . . . . . . . 19
Donning and Removing the ACH . . . . . . . . . . . . . . . . 22
Sizing and Fitting Troubleshooting . . . . . . . . . . . . . . . 26
Replacing Retention System Webbing . . . . . . . . . . . . . 32
Attaching ACH Cover . . . . . . . . . . . . . . . . . . . . . . 34
Installing Front Bracket Assembly Kit . . . . . . . . . . . . . . 36
Installing Eyewear Retention Strap . . . . . . . . . . . . . . . 39
Configuration for Airborne Operations . . . . . . . . . . . . . 42
CHAPTER 3 - MAINTENANCE PROCEDURES
Replacing the Hardware . . . . . . . . . . . . . . . . . . . . 45
Replacing the Pad Suspension . . . . . . . . . . . . . . . . . 47
Replacing the Hook Disk . . . . . . . . . . . . . . . . . . . . 48
Cleaning Instructions . . . . . . . . . . . . . . . . . . . . . . 49
Preventive Maintenance Checks and Services . . . . . . . . . 50
i
TABLE OF CONTENTS (Continued)
CHAPTER 4 - SUPPORTING INFORMATION
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Components of End Item and
Basic Issue Items Lists . . . . . . . . . . . . . . . . . . . 56
Expendable and Durable Items List . . . . . . . . . . . . . . . 60
Tool Identification List . . . . . . . . . . . . . . . . . . . . . . 62
Associated and Repair Items List . . . . . . . . . . . . . . . . 64
ii
HOW TO USE THIS MANUAL
OVERVIEW
This manual contains operating instructions and maintenance
procedures for the Advanced Combat Helmet (ACH).
This manual is divided into the following major sections:
Front Cover. Provides information about the equipment covered
by the TM.
Warning Summary. Provides a summary of all warnings that
apply throughout the manual.
Table of Contents. Lists chapters and page numbers in order of
appearance.
Chapter 1, Description and Theory of Operation. Provides
descriptions, equipment data, and theory of operation information.
Chapter 2, Operator Instructions. Provides sizing information,
donning information, and operating instructions.
Chapter 3, Maintenance Procedures. Provides cleaning and
repair instructions and maintenance procedures.
Chapter 4, Supporting Information. Provides reference
information, Components of End Item (COEI)/Basic Issue Items
(BII) Lists, Associated and Repair Items List, and Expendable and
Durable Items List.
iii
ADVANCED COMBAT HELMET
GENERAL INFORMATION
SCOPE
This manual covers the basic fitting, use, and care instructions for
the Advanced Combat Helmet (ACH), hereafter referred to as the
ACH.
LIST OF ABBREVIATIONS/ACRONYMS
Components of End Item (COEI)
Basic Issue Items (BII)
Advanced Combat Helmet (ACH)
Night Vision Goggle (NVG)
Nuclear, Biological, and Chemical (NBC)
END OF SECTION
iv
CHAPTER 1
DESCRIPTION AND THEORY OF OPERATION
FOR ACH
ACH
EQUIPMENT DESCRIPTION AND DATA
EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND
FEATURES
The ACH is a system that provides ballistic and impact protection.
This system is compatible with the current night vision goggles
(NVGs), communications packages, and nuclear, biological, and
chemical (NBC) defense equipment and body armor.
The ACH provides ballistic protection within the full spectrum of
operational environments.
The ACH allows maximum sensory and situational awareness for
the operator. This includes an unobstructed field of view and
increased ambient hearing capabilities.
The ACH s chinstrap retention system and pad suspension
system provide unsurpassed balance, stability, and comfort.
These systems provide for proper size, fit, and ventilation.
The ACH s pad suspension system provides impact protection
throughout all operational scenarios, including static-line airborne
operations.
1
DESCRIPTION OF MAJOR COMPONENTS
The ACH is made up of the following major components, which
are illustrated below:
" ACH shell
" pad suspension system
" retention system with hardware
" ACH cover
" eyewear retention strap (not shown)
PAD
SUSPENSION
ACH
SYSTEM
COVER
ACH
SHELL
RETENTION
SYSTEM WITH
HARDWARE
Major Components
2
ACH SHELL
HOOK DISKS
ACH Shell
3
CIRCULAR CROWN PAD
(QTY 1 IN ACH)
OBLONG/OVAL PAD
(QTY 4 IN ACH)
TRAPEZOIDAL PAD
(QTY 2 IN ACH)
Pad Suspension System
4
HARDWARE
ELASTIC
(See detail on
BAND
next page)
ELASTIC
BAND
LADDER LOCK
CHINCUP
NAPE PAD
BUCKLE
Retention System
5
RETENTION
SYSTEM
(INSIDE
ACH)
HOLE IN
ACH SHELL
CONICAL
NUT
(INSIDE
ACH)
BALLISTIC
SCREW
(OUTSIDE
ACH)
Hardware
6
FRONT
COVER
RETAINING
Inside View
TAB
of ACH Cover
REAR
COMMUNICATIONS
FLAP*
Rear View
of ACH Cover
* The communications flap is used to store cables from the
headset microphone that is sometimes used with the ACH.
The flap can also be used to secure goggle straps if no eyewear
retention straps are available. Lift the flap and place the goggle
strap under the flap. Re-secure the flap by pressing the hook and
loop together.
ACH Cover
7
SNAP (SOCKET)
SNAP (STUD)
HOLE FOR MOUNTING
TO ACH SHELL
Eyewear Retention Strap
END OF SECTION
8
ACH
THEORY OF OPERATION
This section discusses theory of operation and protective qualities
of the ACH.
This ACH is designed to provide the soldier with ballistic and
impact protection. It is compatible with night vision,
communications, and nuclear, biological and chemical (NBC)
equipment. The small ACH (without the cover) weighs under 3
pounds, the medium weighs 3 pounds, the large weighs 3.3
pounds, and the X-large weighs 3.8 pounds.
The edge cut of the shell has been reduced when compared to
the Helmet, Ground Troops and Parachutists. This enables better
situational awareness through improved field of vision and
hearing.
The shell provides ballistic protection. The pads act as a
suspension system providing sizing and fitting. In conjunction with
the shell, the pad suspension system provides impact protection.
In conjunction with the chinstrap retention system, the pad
suspension system provides stability.
The chinstrap retention system is a four-point design, attaching to
the shell at four locations. In conjunction with the pad suspension
system, the retention system with the H-shaped nape pad
provides improved stability.
END OF SECTION
9
CHAPTER 2
OPERATOR INSTRUCTIONS
FOR ACH
SIZING AND FITTING INSTRUCTIONS
This section provides instructions for choosing the proper size
ACH.
ACH Shell Sizing
Head Measuring Procedure
Use tape measure and caliper to make the following
measurements.
See Chapter 4, Expendable and Durable Items List, for
appropriate NSNs.
Step 1. Soldier must be seated in upright position.
Step 2. Measure head length. Measurement is best made with a
caliper and a ruler. If caliper is not available, an approximate
measurement can be made using a tape measure aligned with the
front and back of head as shown. Record the size measured.
Arrows denote
the proper
alignment of the
caliper or tape
measure.
Measuring Head Length
11
Step 3. Measure head width. Measurement is best made with a
caliper and a ruler. If no caliper is available, an approximate
measurement can be made using a tape measure aligned with
each side of head as shown. Record the size measured.
Step 4. Measure head circumference. Record the size measured.
Arrows denote the
proper alignment of the
caliper or tape measure.
Measuring Head Width
Soldier sits erect with
head level. Measure
circumference by
passing tape measure
just above the eyebrow
and above both ears.
The tape measure
TAPE
must be pulled tight.
MEASURE
Measuring Head Circumference
12
Step 5. Using the chart below, select the ACH size on the basis of
the largest of the three measurements. If a measurement falls on
the dividing line between the two sizes, select the larger size. This
is the proper shell size for the soldier measured.
NOTE
If any measurement falls on the dividing line between sizes, select
the larger size.
Table 1. Head/Shell Sizing
ACH SIZE Head Head Head
Length Width Circumference
Up to 7 ź inches Up to 6 ½ inches Up to 21 ź inches
Small
(184 mm) (162 mm) (538 mm)
From 7 ź inches Up to 6 ½ inches From 21 ź inches
Medium
(184 mm) up (162 mm) (538 mm)
to 7 ¾ inches up to 22 ½ inches
(198 mm) (573 mm)
From 7 ¾ inches Up to 6 ½ inches From 22 ½ inches
Large
(198 mm) (162 mm) (573 mm)
up to 8 ź inches up to 23 ½ inches
(210 mm) (597 mm)
8 ź inches 6 ½ inches 23 ½ inches
X-large
(210 mm) (162 mm) (597 mm)
and over and over and over
END OF SECTION
13
ACH Pad Sizing
The sizes of the pads are as follows:
" thick (also referred to as size 6)
1" thick (also referred to as size 8)
To select pad size:
1. Assemble the ACH in standard pad configuration (see Pad
Configuration in Chapter 2). If other equipment is to be used
with the ACH, such as headset/microphone, evaluate size
with that equipment (if possible).
2. Try on the ACH and evaluate fit. Proper fit is achieved when
the ACH does not sit too high (crown pad does not contact
head or too much of forehead is exposed) or too low (too low
on brow or not compatible with eyewear, etc.) and is not too
tight or too loose (see Sizing and Fitting Troubleshooting in
Chapter 2). Shake head rapidly from side to side to check for
stability. The ACH should not rotate from side to side when
head is shaken. While evaluating fit, be sure to have the
chinstrap retention system cinched down.
END OF SECTION
14
PAD CONFIGURATIONS
This section provides instructions for different pad configurations.
Standard Pad Configuration
WARNING
For airborne and other high risk operations such as air
assault and rappelling/mountaineering, all seven pads must
be worn at all times. Failure to observe this precaution could
result in serious injury or death.
Below is the standard pad configuration, with the pads placed
vertically. The pads may also be placed in other directions as
described on the next page. (See Configuration for Airborne
Operations in Chapter 2 for additional information on pad
placement.)
TRAPEZOIDAL PAD
OBLONG/OVAL
PAD
OBLONG/OVAL
PAD
CROWN
PAD
OBLONG/OVAL
OBLONG/OVAL
PAD
PAD
TRAPEZOIDAL PAD
Standard Pad Configuration
15
Pads can be placed in vertical or horizontal directions (as shown
below) or a combination or at an angle between horizontal and
vertical (diagonal).
The vertical configuration maximizes airflow for better temperature
regulation. The horizontal configuration makes a seal around the
user s head and is better suited for cold weather environments.
It is best to cover hardware with pads in all situations. However,
hardware MUST be covered with pads in high-risk situations.
PADS PLACED PADS PLACED
VERTICALLY HORIZONTALLY
Vertical and Horizontal Pad Placement
16
Alternate Pad Configurations
WARNING
The ACH was impact-qualified using the standard pad
configuration. This pad configuration provides the
required impact protection at all required impact sites.
Alternate pad configurations may not provide optimal
protection at all required impact sites.
Alternate pad configurations are allowed to obtain a better fit or
more comfort.
" Pads can be placed in vertical or horizontal directions (as
shown in illustrations) or a combination or at an angle
between horizontal and vertical (diagonal).
" Up to two pads (front or peripheral) can be removed in
non-risk situations. The circular crown pad must always
remain in the ACH.
" Pads should be placed around the inside of the ACH to
provide optimum comfort and stability.
" It is best to cover hardware with pads in all situations.
However, hardware MUST be covered with pads in high-risk
situations.
The following illustrations show alternate configurations. For
reasons of clarity only, each of the illustrations shows pads in
either horizontal or vertical positions but not in diagonal positions.
However, the pads can be placed diagonally, at any angle.
17
The five-pad configuration is useful in hot climates.
PADS PLACED PADS PLACED
VERTICALLY HORIZONTALLY
Five-Pad Configuration
The six-pad configuration is useful for wearers who have long
heads or when protective masks are worn.
PADS PLACED
PADS PLACED
HORIZONTALLY
VERTICALLY
Six-Pad Configuration
END OF SECTION
18
PAD SUSPENSION ADJUSTMENT
This section provides information about the adjusting the pad
suspension system. This unique suspension system is fully
adjustable. The system has the following requirements and
restrictions:
WARNING
The hardware (nut) inside the ACH where the retention
system webbing attaches to the ACH shell (in four
places) must be covered by padding during airborne and
other high-risk operations such as air assault and
rappelling/mountaineering. The oblong/oval pad must be
placed flush with the rim (edge) of the ACH and completely
cover the hardware See illustrations Pad Placement Over
Front Hardware and Pad Placement Over Rear Hardware.
Failure to observe this precaution could result in serious
injury or death.
OBLONG/OVAL
PAD
HARDWARE
(NUT)
UNDER PAD
Pad Placement Over Front Hardware (Two Places)
19
OBLONG/OVAL
PAD
HARDWARE (NUT)
UNDER PAD
Pad Placement Over Rear Hardware (Two Places)
WARNING
For airborne and other high risk operations such as air
assault and rappelling/mountaineering, all seven pads must
be worn at all times. Failure to observe this precaution could
result in serious injury or death.
WARNING
If you experience fit problems, tightness/looseness, or ACH
profile is too high or too low, refer to Sizing and Fitting
Troubleshooting guidelines.
NOTE
When donning the ACH for the first time in a cold
environment, it is necessary to wear the ACH for a few
minutes or otherwise warm the pads, such as by placing in
pockets, so that the pads will conform to the shape of your
head. As the pads warm up and conform to the shape of
your head, it may be necessary to re-tighten the chinstrap
retention system.
20
NOTE
If you experience hot spots or discomfort, try rearranging the
pad system to accommodate a more comfortable fit. If
discomfort persists, try another shell size. (See Sizing and
Fitting Instructions or Sizing and Fitting Troubleshooting,
Chapter 2.)
END OF SECTION
21
DONNING AND REMOVING THE ACH
This section provides instructions for donning and removing the
ACH, including adjusting the chinstrap to optimize fit and comfort.
Donning: To don (put on) the ACH:
Step 1. Check number and placement of pads (see pad
illustrations in Chapter 2).
Step 2. Prior to donning ACH, loosen all adjustment straps (ends
of chin cup, two ladder-locks in front, two ladder-locks in back,
and the nape pad). Unbuckle chinstrap buckle.
LADDER
LOCK
(4 PLACES)
CHIN CUP
NAPE PAD
BUCKLE
ACH Adjustment Points
22
Step 3. Position ACH on head and buckle chinstrap. Hold ACH in
place with one hand on top of ACH for initial adjustment.
Positioning ACH on Head
NOTE
If you pull too tightly on any strap during Steps 4 and 5 or if
you don t position ACH on head and hold in place with one
hand on top of ACH for initial adjustment as instructed in
Step 3 the ACH may become uncomfortable and tilted on
your head and chin cup may become un-centered.
Step 4. Partially tighten the two back adjustment straps (one side
at a time).
Tightening Back Adjustment Straps
23
Step 5. Partially tighten the two front straps (one side at a time) by
moving the slides up.
Tightening Front Straps
Step 6. With both hands, fully tighten the front and back
adjustment straps.
Tightening Front and Back Straps
24
Step 7. The nape pad can be can be slid up and down along the
rear legs of the chinstrap. It can be positioned according to
personal comfort. When tightened (see figure below) against the
nape by pulling on end of webbing, the nape pad adds additional
stability to the ACH such as when wearing NVGs. Keep the nape
pad away from the ladder-locks while adjusting the chinstrap to
prevent jamming.
Releasing Buckle
Removing: To remove the ACH:
To remove the ACH, unbuckle the chinstrap buckle. Once the
buckle releases, remove the ACH.
END OF SECTION
25
SIZING AND FITTING TROUBLESHOOTING
This section provides sizing and fitting troubleshooting
techniques.
1. If ACH is too tight:
" Try arranging side pads in a horizontal configuration or
diagonal direction (see pad configuration illustrations in
Chapter 2).
" If rearranging the pads does not alleviate the tightness, try the
next larger shell size.
ACH Too Tight
26
2. If too loose (Shake head from side to side while eyes are
closed. If ACH slides on head, it is too loose.)
" Try a thicker pad set.
" Select the next smaller shell size.
ACH Too Loose
27
3. If too high: (i.e., too much forehead exposed, crown does not
touch top of head, or wearer does not see edge of rim):
" Try rearranging pads (horizontal or diagonal see pad
configuration illustrations in Chapter 2.)
" Try a larger shell size.
It is extremely important that the ACH not be sized and fitted to sit
too high on the head. Here are some things to look for:
If too much of forehead is exposed (approximately more than
½-inch above eyebrow), then the ACH is too high.
TOO MUCH
FOREHEAD EXPOSED
ACH Too High (Too Much Forehead Exposed)
28
If crown pad does not hit head (wearer cannot feel pad), then
ACH may be too high.
SPACE BETWEEN PAD
AND HEAD
ACH Too High (Crown Pad Not Touching Head)
29
When fitting, have subject look upward by moving eyes, but
without moving head. If subject cannot see rim of ACH, ACH may
be too high.
WEARER
CANNOT
SEE RIM
ACH Too High (Looking Past Rim)
30
4. If too low: (i.e. ACH too low on brow, ACH not compatible with
eyewear, or has other similar compatibility issues)
" Try larger (thicker) pad set.
" Try rearranging pads (horizontal or diagonal see pad
configuration illustrations in Chapter 2.)
" Try a smaller size ACH.
RIM INTERFERES
WITH VISION
AND EYEWEAR
ACH Too Low
END OF SECTION
31
REPLACING RETENTION SYSTEM WEBBING
This section provides instructions for replacing the ACH s
retention system webbing.
1. Slide the elastic bands off the loose ends of the webbing
2. Unthread the chinstrap retention system webbing from the four
ladder-locks.
3. Lay the ACH on its crown with the front of the ACH away from
you. Drape the replacement retention system over the ACH
with the nape-strap pad facing down on the back/rear of the
ACH and the chinstrap. The buckle is located on the right side
of the ACH. (See Chinstrap Retention Orientation illustration
below)
4. Insert and thread the four legs of the retention system into their
corresponding ladder locks. (See Routing of Retention System
Webbing through Ladder Lock illustration on the next page.)
For illustration of entire assembled ACH with retention and
hardware please refer to Chapter 1. Take care to ensure that
webbing is not twisted.
5. Slide elastic band over loose ends of webbing.
FRONT
BUCKLE
Retention System Orientation
32
Routing of Retention System Webbing Through Ladder Lock
END OF SECTION
33
ATTACHING ACH COVER
This section provides instructions for attaching the camouflage
ACH cover to your ACH.
The following covers are available for the ACH: a universal
camouflage, reversible woodland/desert cover and a white (Artic)
cover.
FRONT OF ACH
ACH Cover
(Outside, Back)
ACH
Cover
(Inside)
HOOK AND LOOP
COMMUNICATIONS
BUTTONHOLES
RETAINING TABS
FLAP
ACH Cover
1. Remove the suspension pads from the inside of the ACH shell.
2. Remove the chinstrap retention system. (See Chapter 2.)
3. Select the camouflage pattern to be worn and orient the cover
so that the desired pattern is on the outside if using the
reversible cover.
4. Align the communications flap with the rear of the ACH shell.
34
5. Pull the cover over the back and sides of ACH shell.
6. Thread each ladder-lock through the corresponding buttonhole
at the edge of the cover.
7. Pull the cover retaining tabs down and attach tabs to hook
disks inside ACH shell. Ensure tight smooth fit of cover by
pulling the retaining tabs until tight.
8. Place suspension pads back into shell. (See Page 15.)
9. Replace retention system webbing. (See Page 32 for
instructions for replacing the retention.)
RETENTION STRAP
THREADED
THROUGH COVER
(4 PLACES)
COVER
RETAINING
TABS
HOOK DISK
ACH Cover Installed
END OF SECTION
35
INSTALLING FRONT BRACKET ASSEMBLY KIT
WARNING
If no NVG Front Bracket is used and the ACH has a hole
for the front bracket plug the hole with the 8-32 x 3/8 long
screw and post. See Chapter 4, Associated and Repair
Items List, for the appropriate part number.
This section provides instructions for installing the front bracket
assembly kit on the ACH.
1. Make sure that the front bracket assembly kit has all the
components. You should have a front bracket assembly, a
screw, and a threaded post (see illustration below). See
Chapter 4, Associated and Repair Items List, for the
appropriate part number.
2. Install the ACH cover on your ACH. See Page 34 for
instructions on attaching the ACH cover.
FRONT BRACKET
ASSEMBLY
THREADED POST
SCREW
Front Bracket Assembly Kit Contents
36
3. Remove the front trapezoidal pad (located inside the center
front of the ACH).
4. Place the front bracket assembly on the ACH over the ACH
cover. Line up the hole in the plate, the front buttonhole in the
cover, and the hole in the ACH shell (see  Front Bracket
Assembly Positioned on ACH illustration in this section). Move
the cover around to line up the buttonhole in the cover.
5. Insert the screw through the front bracket assembly, cover, and
into shell from the outside of the ACH. Insert the threaded post
from inside the ACH. Start to tighten the screw and post (see
 Front Bracket Assembly Positioned on ACH illustration in this
section).
CAUTION
Do not over tighten the screw, or the front bracket assembly
may break.
6. Before completely tightening the screw, ensure that the cleat of
front bracket assembly is tight against the rim of the ACH. (See
 Front Bracket Assembly Positioned on ACH illustration in this
section.) Push the bracket up so that the cleat is tight against
the rim (edge) of the ACH while tightening the screw and post.
It may be helpful to have another person assist with this step.
7. Reinstall the front trapezoidal pad.
37
Post located on
the inside of the
ACH Cover
Screw located on the
ACH and
outside of the ACH and
inserted into
inserted through front
hole in the shell.
bracket assembly and
ACH cover into hole in
the shell.
Front Bracket Assembly Positioned on ACH
END OF SECTION
38
INSTALLING EYEWEAR RETENTION STRAP
This section provides instructions for installing the eyewear
retention strap on the ACH.
1. Make sure you have two eyewear retention straps (see
Chapter 4, Associated and Repair Items List, for the
appropriate part number).
2. Remove the rear pads.
3. If the ACH cover is installed, unthread the rear retention
system webbing from the ladder locks, remove the rear cover
retaining tabs and slide the rear half of the cover up to expose
the two rear screws. You can also remove the cover
completely (see Page 34).
4. Remove one of the two rear screws. Place an eyewear
retention strap over the barrel (shaft) of the screw with the
snap socket and stud facing away from the ACH. (See
Eyewear Retention Strap and Screw Assembly illustration in
this section.)
5. Insert the screw, with the eyewear retention strap attached,
into the hole in the ACH.
6. Place the retention system strap and nut (inside the ACH) on
the screw and tighten until the nut bottoms out on the screw.
(See Chapter 3, which shows screw and nut installation, for
replacing the hardware.)
7. Repeat Steps 4-6 to install the other eyewear retention strap
with the other rear screw.
39
 8. Install the ACH cover. While installing the cover, thread
eyewear retention strap through rear buttonhole next to the
communication flap on the cover. (See ACH with Eyewear
Retention Strap Installed illustration for finished assembly,
Page 41.)
9. Re-thread the ladder locks through the buttonholes at the
edge of the cover and secure the cover retaining tabs.
10. Re-thread the retention system webbing through the ladder
locks.
11. Reinstall the rear pads.
SNAP (STUD)
SNAP (SOCKET) NUT
SCREW
HOLE IN EYEWEAR
RETENTION SYSTEM
RETENTION STRAP
HOLE IN ACH SHELL
Eyewear Retention Strap and Screw Assembly
40
ACH COVER
EYEWEAR RETENTION STRAP
SCREW (SHOWN
UNDER COVER)
BUTTONHOLE NEXT TO
COMMUNICATION FLAP
ACH With Eyewear Retention Strap Installed
41
CONFIGURATION FOR AIRBORNE OPERATIONS
This section provides instructions for configuring the ACH for
airborne operations as well as other high-risk operations such as
air assault and rappelling/mountaineering. No other parts or
components are required for airborne use of the ACH.
WARNING
The hardware (nut) inside the ACH where the chinstrap
retention system webbing attaches to the ACH shell in four
places must be covered by padding during airborne and other
high risk operations such as air assault and rappelling/
mountaineering. The oblong/oval pad must be placed flush with
the rim (edge) of the ACH and completely cover the
hardware See illustration Pad Placement over Hardware (Front)
and Pad Placement over Hardware (Rear). Failure to observe this
precaution could result in serious injury or death.
WARNING
All seven pads must be worn during airborne operations and
should be worn during other high risk operations such as air
assault and rappelling/mountaineering. Failure to observe this
precaution could result in serious injury or death.
WARNING
The rear pads must be placed flush with the rim (edge) of the
ACH for airborne operations. If you experience ACH rotation
during airborne operations the rear pads can be placed so that
they extend ½ beyond the rim of the ACH. Placement of the rear
pads flush or beyond the rim (edge) of the ACH prevents the hard
shell from hitting your neck. (See Pad Placement over Hardware
(Front) and Pad Placement over Hardware (Rear) illustrations.)
END OF SECTION
42
PAD
HARDWARE
Pad Placement Over Front Hardware Hardware (Two Places)
PAD
HARDWARE
Pad Placement Over Hardware (Two Places)
43
CHAPTER 3
MAINTENANCE PROCEDURES
FOR ACH
MAINTENANCE PROCEDURES
REPLACING THE HARDWARE
This section provides instructions for replacing the ACH s
hardware (screw or nut).
NOTE
To replace hardware, use a standard flathead screwdriver. If
this tool is unavailable, a coin may be used.
You may need to use a second screwdriver to hold the nut in
place while you remove the screw. (See Hardware
Installation illustration in this section.)
1. Remove the retention system as described in Chapter 2.
2. Remove the screw with a standard flathead screwdriver.
3. Replace screw and nut. Ensure the proper orientation hardware
and retention system. (See Hardware Installation illustration in
this section.) Tighten the screw until the nut bottoms out on the
screw.
4. Inspect the screws to ensure tightness. If loosening persists,
use the sealing compound (thread-locking compound; see
Page 61, Expendable and Durable Items List). Follow directions
on container.
45
SECOND
SCREWDRIVER
RETENTION
CONICAL
SYSTEM
NUT
STRAP
BALLISTIC
SCREW
Hardware Installation
END OF SECTION
46
MAINTENANCE PROCEDURES
REPLACING THE PAD SUSPENSION
This section provides information on replacing the pad
suspension.
Replacing Pad Suspension
NOTE
One side of each pad contains labeling. ONLY THE LABELED
SIDE OF THE PAD WILL BE ATTACHED TO THE HOOK DISKS
ON THE ACH SHELL.
1. Pull the individual pads off the hook disks inside the ACH.
2. Press the replacement pads against the hook disks. (See
Chapter 2 for Pad Configurations and Pad Suspension
Adjustment.)
END OF SECTION
47
MAINTENANCE PROCEDURES
REPLACING THE HOOK DISK
This section provides instructions for replacing worn-out hook
disks inside the ACH shell.
Replacing Hook Disk
1. Remove the old hook disks.
2. Clean the inside of the ACH shell with mild soap and water.
Allow to dry thoroughly.
3. Press the new hook disks firmly to the inside of the ACH shell
in approximately the same locations as the old ones.
END OF SECTION
48
MAINTENANCE PROCEDURES
CLEANING INSTRUCTIONS
This section provides instructions for cleaning the ACH.
ACH Shell
NOTE
A small brush is useful in removing dirt from the hook disks
on the inside of the shell.
1. Clean with mild soap and water. Use a soft brush or cloth.
2. Allow to air dry.
Chinstrap, ACH Cover, and Pad Suspension
1. Clean with mild soap and water. Wash by hand or in machine in
the gentle cycle, cold water.
2. Allow to air dry. DO NOT MACHINE DRY.
Keeping the hook and loop clean will help to maintain its ability to
stick together.
END OF SECTION
49
MAINTENANCE PROCEDURES
PREVENTIVE MAINTENANCE CHECKS AND SERVICES
INTRODUCTION
General
Preventive maintenance checks and services (PMCS) are
performed to keep the ACH in operating condition. The checks
are used to find, correct, and report problems. The operator is to
do the PMCS tasks shown in PMCS Table 1. PMCS is to be done
before, during, and after use of the ACH.
Before you use the ACH, perform PMCS.
During use of the ACH, periodically perform PMCS.
After you have used the ACH, perform PMCS.
PMCS Column Description
ITEM  The order the PMCS should be performed and a
reference number for maintenance forms. INTERVAL  Tells
when the check should be performed. ITEM TO BE CHECKED
OR SERVICED  Tells which items to perform the PMCS
procedure on. PROCEDURE  Tells the procedure to perform. If
item cannot be repaired, it must be replaced. EQUIPMENT NOT
READY IF  Tells what conditions render the ACH unfit to perform
the mission.
50
Table 1. Preventive Maintenance Checks and Services
ITEM INTERVAL ITEM TO BE PROCEDURE EQUIPMENT NOT
NO. CHECKED OR READY/
SERVICED AVAILABLE IF
1 Before Chinstrap Check for: Chinstrap webbing
Retention 1) Cuts, frays or has cuts, frays, or
System other damage or other damage.
loose or damaged
stitching in the
webbing. If
webbing is frayed
more than ½ or
has a discernable
cut, or loose or
damaged
stitching, replace
the chinstrap
retention system.
2) Cracked, worn, Hardware or buckle
or damaged is cracked, worn, or
hardware damaged.
(ladderlock, nut,
screw) and
buckle. Replace
the chinstrap
retention system.
3) Loose screws. Screws are loose.
Tighten screws.
51
Table 1. Preventive Maintenance Checks and Services
ITEM INTERVAL ITEM TO BE PROCEDURE EQUIPMENT NOT
NO. CHECKED OR READY/
SERVICED AVAILABLE IF
2 Before Pads Cuts, tears or Pads are torn, cut
other damage to or otherwise
outer fabric or damaged.
inner foam. If
pads are torn or
cut, exposing the
inner padding,
replace.
3 Before Shell 1) Gouges, Gouges, scrapes,
scrapes, cracks, cracks,
delamination or delamination or
other damage to other damage
shell. If gouges, extends below the
scrapes, or surface (below the
damage extends paint).
below the surface
(below the paint),
replace the ACH
shell.
2) Loose or Edging is
damaged edge excessively loose or
beading. Replace damaged.
the ACH shell.
3) Loose or Hook disks are
damaged hook damaged such that
disks. Replace they will not
the hook disks. securely hold the
pads in place.
52
Table 1. Preventive Maintenance Checks and Services
ITEM INTERVAL ITEM TO BE PROCEDURE EQUIPMENT NOT
NO. CHECKED OR READY/
SERVICED AVAILABLE IF
4 Before Cover Cuts, frays or Excessive cuts,
other damage to frays, or other
the fabric or cut damage to the
or frayed fabric or cut or
stitching. Refer to frayed stitching.
higher level
maintenance for
repair.
5 During Chinstrap Inspect for Chinstrap
Retention damaged components are
System components (see damaged. See
Item 1) above.
6 After Chinstrap Perform all PMCS See Items 1-4.
Retention steps in Items 1-4
System, Pads, after use.
Hardware,
Shell.
END OF SECTION
53
CHAPTER 4
SUPPORTING INFORMATION
FOR ACH
SUPPORTING INFORMATION
REFERENCES
This section lists related field manuals, forms, technical manuals,
and miscellaneous publications.
FIELD MANUALS
FM 4-25.11 First Aid for Soldiers
END OF SECTION
55
SUPPORTING INFORMATION
COMPONENTS OF END ITEM AND BASIC ISSUE ITEMS LISTS
INTRODUCTION
Scope
This section lists COEI and BII for the ACH to help you inventory
items for safe and efficient operation of the equipment.
General
The COEI and BII information is divided into the following lists:
Components of End Item (COEI). This list is for information
purposes only and is not authority to requisition replacements.
These items are part of the ACH. As part of the end item, these
items must be with the end item whenever it is issued or
transferred between property accounts. Items of COEI are
removed and separately packaged for transportation or shipment
only when necessary. Illustrations are furnished to help you find
and identify the items.
Basic Issue Items (BII). These essential items are required to
place the ACH in operation, operate it, and to do emergency
repairs. Although shipped separately packaged, BII must be with
the ACH during operation and when it is transferred between
property accounts. Listing these items is your authority to
request/requisition them for replacement based on authorization
of the end item by the TOE/MTOE. Illustrations are furnished to
help you find and identify the items.
Explanation of Columns in the COEI List and BII List
Column (1) Illus Number. Gives you the number of the item
illustrated.
Column (2) National Stock Number (NSN). Identifies the stock
number of the item to be used for requisitioning purposes.
56
Column (3) Description, CAGEC, and Part Number. Identifies
the Federal item name (in all capital letters) followed by a
minimum description when needed. The stowage location of COEI
and BII is also included in this column. The last line below the
description is the CAGEC (Commercial and Government Entity
Code) (in parentheses) and the part number.
Column (4) Usable On Code. When applicable, gives you a code
if the item you need is not the same for different models of
equipment. (Add the following only as applicable. Replace Xs with
appropriate codes and model numbers.)
Column (5) Unit of Issue (U/I). Indicates the physical
measurement or count of the item as issued per the National
Stock Number shown in column (2).
Column (6) Qty Rqr. Indicates the quantity required.
57
3
2
1
Components of End Item and Basic Issue Items
Components of End Item List
(1) (2) (3) (4) (5) (6)
Illus National Stock Description, CAGEC, and Usable U/I QTY
Number Number Part Number on rqr.
Code
1 Retention System, N/A ea 1
97427/05D11948-1
2 8470-01-476-5643 Pad Suspension System, N/A set 1
3/4", 97427/05C11950-1
8470-01-476-5648 Pad Suspension System, 1", N/A set 1
97427/05C11950-2
58
Basic Issue Items (BII) List
(1) (2) (3) (4) (5) (6)
Illus National Stock Description, CAGEC, and Usable on U/I QTY
Number Number Part Number Code
8415-01-515-4662 Cover, ACH, Reversible, with N/A ea 1
3
communication flap, size S/M,
97427/04A11921-1
8415-01-515-4663 Cover, ACH, Reversible, with N/A ea 1
communication flap, size L/XL,
97427/04A11921-2
8415-01-515-4671 Cover, ACH, Reversible, N/A ea 1
without communication flap,
size S/M, 97427/04D11921-3
8415-01-515-4674 Cover, ACH, Reversible, N/A ea 1
without communication flap,
size L/XL, 97427/04D11921-4
8415-01-521-8806 Cover, ACH, Camouflage, N/A ea 1
Universal Print,
Non-Reversible, S/M, with
communication flap
8415-01-521-8808 Cover, ACH, Camouflage, N/A ea 1
Universal Print,
Non-Reversible, L/XL, with
communication flap
8415-01-515-4286 Cover, ACH, White, N/A ea 1
Non-reversible, with
communication flap, size S/M
8415-01-515-4288 Cover, ACH, White, N/A ea 1
Non-reversible, with
communication flap, size L/XL
8415-01-515-4289 Cover, ACH, White, N/A ea 1
Non-reversible, without
communication flap, size S/M
8415-01-515-4290 Cover, ACH, White, N/A ea 1
Non-reversible, without
communication flap, size S/M
Use and Care Manual N/A ea 1
(TP0271)
END OF SECTION
59
SUPPORTING INFORMATION
EXPENDABLE AND DURABLE ITEMS LIST
INTRODUCTION
Scope
This section lists expendable and durable items that you will need
to operate and maintain the ACH. This list is for information only
and is not authority to requisition the listed items. These items are
authorized to you by CTA 50-970, Expendable/Durable Items
(Except Medical, Class V Repair Parts, and Heraldic Items), or
CTA 8-100, Army Medical Department Expendable/Durable Items.
Explanation of Columns in the Expendable/Durable
Items List
Column (1) Item Number. This number is assigned to the entry
in the list and is referenced in the narrative instructions to identify
the item.
Column (2) Level. This column identifies the lowest level of
maintenance that requires the listed item (include as applicable:
C = Operator/Crew, O = Unit/AVUM, F = Direct Support/AVIM,
H = General Support, D = Depot).
Column (3) National Stock Number (NSN). This is the NSN
assigned to the item which you can use to requisition it.
Column (4) Item Name, Description, Commercial and
Government Entity Code (CAGEC), and Part Number (P/N).
This column provides the other information you need to identify
the item.
Column (5) Unit of Issue (U/I). Indicates the physical
measurement or count of the item as issued per the National
Stock Number shown in column (3).
60
Table 1. Expendable and Durable Items List
(1) (2) (3) (4) (5)
ITEM LEVEL NATIONAL ITEM NAME, U/I
# STOCK DESCRIPTION,
NUMBER CAGEC, PART
NUMBER
1 C Cloth ea
2 C Mild Soap ea
3 C Soft Brush ea
4 C 8030-01-104-5392 Sealing Compound bx
END OF SECTION
61
SUPPORTING INFORMATION
TOOL IDENTIFICATION LIST
INTRODUCTION
Scope
This section lists all common tools and supplements and special
tools/fixtures needed to maintain the ACH.
Explanation of Columns in the Tool Identification List
Column (1) Item Number. This number is assigned to the entry
in the list to identify the item.
Column (2) Item Name. This column lists the item by noun
nomenclature and other descriptive features.
Column (3) National Stock Number. This is the National Stock
Number (NSN) assigned to the item; use it to requisition the item.
Column (4) Part Number/CAGEC. Indicates the primary number
used by the manufacturer (individual, company, firm, corporation,
or Government activity) which controls the design and
characteristics of the item by means of its engineering drawings,
specifications, standards, and inspection requirements to identify
an item or range of items. The manufacturer s Commercial and
Government Entity Code (CAGEC) is also included.
Column (5) Reference. This column identifies the authorizing
supply catalog or RPSTL for items listed in this section.
62
Tool Identification List
ITEM ITEM NATIONAL PART REFERENCE
NO. NAME STOCK NUMBER NUMBER/
CAGEC
1 Screwdriver
2 Caliper 5210-01-434-9493
Measuring 8315-00-782-3520
tape
END OF SECTION
63
SUPPORTING INFORMATION
ASSOCIATED AND REPAIR ITEMS LIST
1
2
15
14
3
4
11
5
7
10, 13
6
9, 12
8
ACH Repair Items
64
Associated and Repair Items List
ITEM NOMENCLATURE QTY. NATIONAL
# STOCK NUMBER
1 ACH, Small 1 8470-01-529-6302
ACH, Medium 1 8470-01-529-6329
ACH, Large 1 8470-01-529-6344
ACH, X-Large 1 8470-01-529-6365
2 ACH Shell, Small 1 8470-01-523-0068
ACH Shell, Medium 1 8470-01-523-0070
ACH Shell, Large 1 8470-01-523-0071
ACH Shell, X-Large 1 8470-01-523-0075
3 21 8470-01-506-6742
Hook Disk
4 Screw, Shoulder, 10-32 4 8470-01-541-9238
5
Conical Nut 4 8470-01-541-9320
6 NVG Mount Bracket 1
5430-01-509-1467
(includes screw and post)
7 Eyewear Retention Strap, 1
8415-01-487-1605
Camouflage Green
1
Eyewear Retention Strap, Light Tan 8415-01-521-8801
Eyewear Retention Strap, 1
8415-01-521-8802
Foliage Green
8 Pad Set, 3/4" 1 8470-01-476-5643
Pad Set, 1" 1 8470-01-476-5648
9 Trapezoidal Pad, 3/4" 2 8470-01-506-6851
10 Oblong/Oval Pad, 3/4" 4 8470-01-506-6454
65
Associated and Repair Items List (Continued)
ITEM NOMENCLATURE QTY. NATIONAL
# STOCK NUMBER
11 Crown Pad, 3/4" Thick 1 8470-01-506-6626
12 Trapezoidal Pad, 1" 2 0470-01-506-6855
13 Oblong/Oval Pad, 1" 4 8470-01-506-6456
14 Retention Assembly 1 05D11948-1
Cover, ACH, Reversible, with 8415-01-515-4662
15 1
communication flap, size S/M
Cover, ACH, Reversible, with 1 8415-01-515-4663
communication flap, size L/XL
Cover, ACH, Reversible, without 1 8415-01-515-4671
communication flap, size S/M
Cover, ACH, Reversible, without 1
8415-01-515-4674
communication flap, size L/XL
1
Cover, ACH, Foliage Green, S/M 8415-01-521-8806
Cover, ACH, Foliage Green, L/XL 1 8415-01-521-8808
1
Cover, ACH, non-reversible, white, 8415-01-515-4286
with communication flap, S/M
1
Cover, ACH, non-reversible, white, 8415-01-515-4288
with communication flap, L/XL
1
Cover, ACH, non-reversible, white, 8415-01-515-4289
without communication flap, S/M
Cover, ACH, non-reversible, white, 1 8415-01-515-4290
without communication flap, L/XL
END OF SECTION
66
TP0271 REV. 2 FEBRUARY 2007